• Sim Elliott

Butterflies (and a family of Spotted Flycatchers) on Chantry Hill, West Sussex. 06.09.21

I went for a walk with my friend to Chantry Hill, near Storrington; with the intention of spotting Butterflies, as it is highlight in The Butterflies of Sussex: A Twenty-First Century Atlas (2017) Michael Blencowe and Neil Hulme as one of the best places in Sussex to see butterflies.


For more information about the butterflies of Chantry Hill, see: Butterfly Conservation - Sussex Branch (sussex-butterflies.org.uk)'s page on Chantry Hill.


For recent bird sittings at Chantry Hill see: Chantry Hill Birdwatching Site - BirdGuides


Here is a map of Chantry Hill; our walking route is shown in orange.


Map is a screen shot of Google Maps satellite view; see: Google Maps


This maps shows just how much wild-flower rich chalk grassland habitat has been lost to arable farming in the South Downs


Walking east - early afternoon (very hot)


We saw many Meadow Browns, Maniola jurtina


Meadow Brown in Ragwort



A Small Heath, Coenonympha pamphilus


A Meadow Brown


This is the roots of a tree (Hazel, I think) that fell over (and is horizontal to the ground) and its vertical new growth, at 90 degrees, since its fall.



The fruit of a Roman tree, Sorbus aucuparia, (I think); not yet ripe.


This is a dead/dying tree; probably Ash, Fraxinus excelsior; (dying possible die to ash die back, caused by the fungus Hymenoscyphus fraxineus; in which there was a family group, seemingly of two adult and thee juvenile Spotted Flycatchers, Muscicapa striata


At first glance, spotted flycatchers might seem dull brownish-grey and, well, a bit boring. It's better to think of them as beautiful in an understated way. Watch them for a short period and you'll be charmed by their fly-catching antics. Spotted flycatchers fly from a high perch, dash out to grab a flying insect and return to the same spot. Spotted Flycatcher Facts | Muscicapa Striata - The RSPB


We observed the fly catchers making the characteristic short flights to grab insects and then returning to the tree; and the birds catching insects from the tress branches; we wondered whether a dead/dying tree would provide an abundance of insects for the flycatchers; we also saw them fly to another dead/dying tree nearby, seemingly of the same species.










The other tree to which the Spotted Flycatchers flew.


The Flycatchers also perched in a Rowan (I think) tree Sorbus aucuparia





Here are three Red Kites, Milvus milvus, that my experienced birding friend spotted.

The Red Kite has made a remarkable recovery, following species re-introduction, from being regionally extinct in Sussex, to now be a quite regular spot.


Red Kite Population Trends - The RSPB: The red kite suffered from intensive human persecution through much of its world range, which is mainly in Europe, until the mid-1950s, but especially so between 1850 and 1900


Decline


This resulted in the species becoming extinct in several countries following a marked long-term decrease in range and numbers.


In the UK the red kite was a valued scavenger during the Middle Ages that helped keep streets clean and was protected by a royal decree; killing a kite attracted capital punishment. However, by the 16th century a bounty was placed on its head and, in common with many other birds of prey, it was relentlessly persecuted as 'vermin'.


The persecution continued through the following centuries largely by game keepers, who wrongly accused them of taking game. As the kite became rarer, it became a target for taxidermists and egg collectors, whose actions hastened the species towards extinction. Consequently, the red kite became extinct in England in 1871 and in Scotland in 1879. By 1903 when protection efforts started, only a handful of pairs were left in remote parts of central Wales.


The small remnant population survived the persecution in the old oakwoods in the undisturbed upland valleys of mid-Wales, but despite extensive efforts, the numbers remained extremely low. The tightest genetic bottle-neck came in the 1930s. Even though several pairs survived, DNA analysis has since discovered that the entire Welsh population was derived from a single female bird. The population did not exceed 20 pairs until the 1960’s, when it started slowly to increase.


Recovery.


Despite extensive efforts, the numbers remained extremely low. The tightest genetic bottle-neck came in the 1930s. Even though several pairs survived, DNA analysis has since discovered that the entire Welsh population was derived from a single female bird. The population did not exceed 20 pairs until the 1960’s, when it started slowly to increase.


There were many reasons for the slow recovery. The population inhabited an area where the climatic conditions and poor food availability depressed breeding success and prevented the birds from expanding their range. Until about 1950 when protection measures were starting to take effect, illegal poisoning, egg collecting and shooting of adults for taxidermy were severely affecting the population.


During the 1950s the rabbit myxomatosis outbreak devastated a main food supply of the kites. This was followed by poor breeding success in the early 1960s, thought to be caused by effects of organochlorine pesticides. It was for a long time believed that the lack of genetic variability caused by the bottle-neck had resulted in the low reproductive rate.

However, once the species had successfully spread to more productive land at lower altitudes, it became obvious that this was almost entirely due to poor habitat conditions. By the mid-1990s there were more than 100 breeding pairs in Wales, and 350-400 pairs by 2003.

Due to the low rate of chick production the Welsh population appeared to be unable to spread out of Wales to recolonise its former range. The re-introduction programme run by RSPB, Natural England and Scottish Natural Heritage, with support and sponsorship from many other bodies, started in 1989 and has helped to establish red kites in several areas of England and Scotland, and their range and numbers are slowly expanding.

Consequently, the red kite’s future as a British breeding species is now much brighter with numbers rising 1026 per cent from 1995-2014. Red Kite Population Trends - The RSPB



Cows and Calves Moo!

Yellow Wagtails have been sighted around cattle on Chantry Hill; bit we saw known today.


Tis photo shows the cows at the top of the scarp slope (the steep slope) of the South Downs escarpment. In the distance ate the Weald (with Ashdown Forest) and in the further distance the North Downs. The geography, geology and biology of the South Downs make it a very special environment.:


Geographical features of chalk down land (from Case study: chalk in the South Downs - Rock types found in the British Isles - GCSE Geography Revision - BBC Bitesize):

  • Chalk is a sedimentary rock made of calcium carbonate.

  • It is porous and allows water to penetrate into the rock. For this reason, surface streams (winterbournes) are only visible when the rock is saturated.

  • Dry valleys are a common feature. These were eroded by fast-flowing surface streams towards the end of the last Ice Age.

  • Where the chalk (permeable) meets an impermeable rock (frequently clay) springs form and can be seen when rivers begin to flow at the surface.

  • Chalk is eroded by solution.

  • Soils are thin which means vegetation is mainly grasses.

  • Chalk forms gentle hills inland (eg the South Downs in southern England) and steep cliffs at the coast (eg the Seven Sisters in Sussex).

  • Chalk escarpments have a gentle slope (or dip) on one side and a steeper slope (or scarp) on the other.

  • Chalk beds are good natural aquifers (underground areas that allow storage of water due to the porous nature of the rock).

Human activity

  • Pastoral farming - Mainly sheep, racehorses and some cows are farmed. Soils are too thin to allow much arable farming.

  • Settlements - Where chalk meets clay, spring-line settlements (where a ridge of permeable rock lies over impermeable rock and a line of springs form along the boundary between the two) can be seen, eg Fulking in West Sussex

  • Quarrying - Chalk with flints is a strong building material used in cement manufacture.


The biodiversity of chalk downland (from Chalk Downland – Learning Zone (southdowns.gov.uk):


Although there appears to be a lot of chalk in the south of England, it is rare in the world as a whole. Chalk grassland is one of the richest habitats of Western Europe, containing many different types of plant and animal. However, not much of it is left, so we need to look after what remains. In the South Downs National Park 4% of the land is chalk grassland.


Chalk grassland only occurs on thin soils covering chalk rocks, as in the South Downs. These soils are well drained and poor in plant foods. As the rainwater soaks through the chalk it takes with it the minerals needed for plants to grow. So the plants which do manage to grow on this poor soil are in strong competition with their neighbours for the plant foods which they need.


This high level of competition results in very many different types of plants growing in a small area because no one plant can outgrow the others. If the soil was deeper and richer or if fertiliser was put on, a few strong plants would take over and the variety would be lost.

In chalk grassland the short, springy grass supports many animals and plants. The right amount of grazing by animals is essential to keep the grass short and to prevent the growth of unwanted plants. Chalk grassland may contain up to 40 different kinds of plants per square metre. This diversity means that there are also many types of insect. You can find rare plants such as the round-headed rampion, orchids ranging from the burnt orchid and early spider orchid to autumn lady’s tresses, and butterflies including the Adonis blue and chalkhill blue.


Scrub consists of common low-growing shrubs or bushes such as hawthorn, blackthorn and the yellow-flowered gorse. However, we must not underestimate the value of scrub, because many different types of plant and animal live in or near it. It should be actively conserved and managed, to make sure it does not spread too much across the delicate grassland.


Walking west - later afternoon (temperature cooling)


In the afternoon, as in the morning, we herd the continuous calling of a juvenile Buzzard, somewhere in the coomb on the north scarp of Chantry Hill. It sounded like a petulant teenager pestering its parents for food; but perhaps its parents had gone; and it was dealing with foraging on its own; not seemingly happily.


After initially not seeing many butterflies on our eastward walk, we saw many more butterflies and insects later in the afternoon It may have been the lower temperature that increased abundance and diversity of what we saw, or it may have been that the scarp slope coombe that we saw more butterflies on offered more wild flowers, of its orientation (the direction the slope faced) was more favourable to butterflies; or a combination of these factors. We saw Small Heaths; Meadow Browns and Small Whites and a Common Blue (wings closed); we also saw a Brown Argus but I didn't get a photo of it.


In the "jungle" of the South Down's lush wild-flower meadows this Red Tailed Worker Bumblebee, Bombus lapidarius, drinks the nectar of Red Clover, Trifolium pratense; one of the Down's most common plants and one of the most important food sources for short-medium tongued bumblebees; with its short corollas. And in return this bumblebee will pollinate the clover with its furry body. In about 6 weeks all male and worker bumblebees and older queens will have died, and only newly mated queens will survive and hibernate for the winter. (Only Buff-tailed bumblebees, Bombus terrestris, can remain active throughout the year).



Small Heath, Coenonympha pamphilus, on Wild Marjoram, Origanum vulgare


A Small Heath I think - Coenonympha pamphilus on Field Scabious, Knautia arvensis


Small Heath, Small White, Pieris rapae, and Common Blue, Polyommatus icarus (wings closed) - I think




Common Blue, probably, Polyommatus icarus


Small Heath


I think this is a type of ichneumon wasp. I only know that is is because I asked a question in the Bees, Wasps and Ants Recording Society Facebook Group; gerat groip.


Ichneumonidae, also known as the ichneumon wasps or ichneumonids, is a parasitoid wasp family within the insect order Hymenoptera. This insect family is among the most species-rich branches of the tree of life. At the same time, it is one of the groups for which our knowledge most severely lags behind their actual diversity. The roughly 25,000 species described today probably represent less than a quarter of their true richness, but reliable estimates are lacking, as is much of the most basic knowledge about their ecology, distribution and evolution. Ichneumonid wasps, with very few exceptions, attack the immature stages of holometabolous insects and spiders, eventually killing their hosts. They thus fulfil an important role as regulators of insect populations, both in natural and semi-natural systems, making them promising agents for biological control. Ichneumonidae - Wikipedia


A Carder Bumblebee, probably a Common Carder, Bombus pascuorum, on Red Clover


A Small Heath, Coenonympha pamphilus, on Yarrow



A Goldfinch, Carduelis carduelis


A Wheatear, Oenanthe oenanthe, in characteristic position, on a a fence. In a few days or weeks this Wheatear will be heading off to Africa for the winter


Clouds


16 views